Fluid purification media and systems and methods of using same

ABSTRACT

A fluid purification system, comprising: a first fluid purification media comprising a rigid porous purification block, comprising: a longitudinal first surface; a longitudinal second surface disposed inside the longitudinal first surface; and a porous high density polymer disposed between the longitudinal first surface and the longitudinal second surface; a second fluid purification media, comprising a fibrous, nonwoven fabric disposed adjacent to the first surface of the first fluid purification media, the second surface of the first purification media, or both.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority under 35 U.S.C. §119(e) to U.S.Provisional Application No. 61/333,570, filed May 11, 2010, the entirecontent of which is incorporated herein by reference.

BACKGROUND

1. Field

Disclosed herein is a purification media comprising a rigid porouspolymeric block having an exterior surface and an interior surface, andcontaining porous, polymeric fabricated to have a wall that is thin, anda pressure drop between the exterior surface and the interior surfacethat is low, when compared to conventional commercial carbonpurification blocks. In particular embodiments, the rigid porouspolymeric block is desirably coupled with an additional materialdisposed on the exterior or interior surface thereof and in particularwith a nonwoven fabric containing, an active material, such asaluminum-containing fibers or particles. These aluminum-containingparticles or fibers may be in the form of metallic aluminum, alumina,aluminosilicates, or combinations of these. The purification media issuitable for purifying fluids, such as water, thereby removing one ormore contaminants from the fluid and for reducing scale formation inequipment in contact with such purified water.

2. Description of Related Art

Diarrhea due to water-borne pathogens in unsafe drinking water is aworldwide problem for many people, particularly in developing countriesand emerging economies. While a number of different technologies areavailable for purifying water, most of these involve some form ofmechanical filtration or size exclusion. Such techniques typicallyinvolve the use of submicron filters to remove pathogens. These filters,in turn, require elevated water pressure, particularly for point-of-use(POU) water filters, where clean water is expected to flow from a supplysource within seconds of being turned on.

Various purification media have been proposed that use blocks ofactivated carbon particles, zeolites, metal oxides, and other materials.Often, these materials purify fluids by one or more mechanisms,including size exclusion, physical entrapment, or chemical reaction ofthe contaminants. The latter two mechanisms generally require somephysical interaction between the active purification elements (e.g.,carbon particles) within the purification media and thecontaminant-containing fluid to be purified.

The particles of active purification elements may be dispersed within,or agglomerated by, a binder of some sort, typically a polymeric binder.The design of these media is complex and difficult, typically requiringtrade-offs between properties such as the activity of the filtrationmedia in removing contaminants and the pressure drop of fluid across thepurification media. For example, decreasing the average particle size ofparticles in the purification media may increase their activity inremoving contaminants by increasing the specific surface area of theparticles that is exposed to contaminant-containing fluid. However, suchan approach may result in increased pressure drops across thepurification media, which actually decreases the flow rate of fluid thatmay be purified using the purification media. This can lead to the needfor multiple filtration systems in order to purify a commerciallyacceptable amount of fluid. Other design problems include balancing theneed for structural integrity of the purification media under fluidpressure with the need for fluid to be able to penetrate thepurification media and come into contact with the active purificationelements therein.

The need to reduce pressure drop across the purification media isparticularly acute in filtration systems that are to be used indeveloping countries and/or countries with emerging economies. Suchsystems are often used where the available water pressure is extremelylow, typically only a fraction of the water pressure that is generallyavailable in developed countries. For example, municipal water pressurein Mexico City is generally 14-16 psi. Water pressure in Mumbai isgenerally 12-16 psi. The availability of a low pressure droppurification media would allow for water purification at available waterpressures in developing countries without the need to use additionalenergy pumping the water to a pressure that is generally available indeveloped countries.

For example, water purification media for use in refrigeration systems,such as residential and commercial refrigerators and freezers containingwater lines, ice makers, and the like, generally require purificationmedia that are capable of processing large amounts of water over asignificant period of time without the need to change the filterfrequently. A relatively low pressure drop in such systems is desirablein emerging economies because of the low water pressure generallyavailable in such countries.

For example in a commercial point of use water purification in the U.S.,the available water pressure is typically around 60 psi. However,purification media designed for use under such pressures would notprovide adequate water flow in, e.g., Brazil, where the typicallyavailable water pressure is from 7-15 psi. Similarly, a purificationmedia that is designed to require a water pressure of 60 psi to produceadequate flow would be unsuitable for use in a water line in arefrigerator in these countries, because water at a much lower pressureis generally all that is available.

At least part of the reason for the inability of conventional waterpurification systems to operate effectively under low water pressureconditions is the higher design pressure drop noted above. However, thishigh pressure drop is not simply a function of the design parameters ofconventional purification media, but is a function of the particularactive purification materials used therein. For example, purificationmedia containing activated carbon derived from coal and the likeaccording to conventional methods and used in conventionally designedpurification media would yield a purification media that provides littleor no water flow at a water pressure of 10 psi. In this regard,conventional purification media that are designed to remove bacteriafrom water and are rated at 0.2 micron will not provide adequate flow(if any) at a inlet pressure of 10 psi.

Another reason for the lack of effectiveness of conventional carbonblock filters in emerging economies is the high water turbidity oftenencountered there. This can be due to a number of factors, and may beassociated with the presence of pathogens or other contaminants in thewater which should be removed to render it safer.

While a combination of a pleated filter element and a carbon blockfilter has been proposed in U.S. Patent Application Publication No.2004/0206682. However, the arrangement suggested therein places thepleated filter element around the outer surface of the carbon blockfilter, so that incoming water encounters the pleated filter block priorto encountering the carbon block filter. Such an arrangement results inclogging and/or exhaustion of the pleated filter with contaminants,resulting in insufficient water flow through the filtration system.

While not wishing to be bound by theory, it is believe that analternative to impaction and sieving is electrokinetic adsorption, wherethe media is charged and particles opposite to that charge are attractedand adsorbed. Membranes have been modified to provide someelectropositive functionality, but none appear to be suitable for lowpressure operating.

Examples of such materials are disclosed in U.S. Pat. Nos. 6,838,005;7,311,752; 7,390,343; and 7,601,262. These materials, when used as waterfiltration media, have been found by the present inventions to beunsuitable for low pressure use, despite any suggestions to the contraryin the above cited documents. The present inventors have found that,even at low input pressures, the materials are subject to unsuitableamounts of compression and distortion, so that they are ineffective forpractical use. In addition, the solution to this problem suggested bythe patentees (placing multiple layers of the fabric in series) resultsin a significant pressure drop (e.g., 80% of incoming water pressure),making the material unsuitable for a low pressure installation. Inaddition, the extra layers of nonwoven fabric substantially increase thecost of this proposed solution. The nonwoven fabrics are disclosed tocontain nanoalumina fibers.

Attempts to use microbiological interception filters are described inU.S. Pat. Nos. 6,913,154 and 6,959,820. However, these attempts use aso-called silver-cationic material-halide complex. Such a complex isdifficult and expensive to prepare and use.

Another problem typically occurring in water supply systems and incirculating water systems relates to the formulation of mineral scale.Dissolved solids in the water can precipitate onto surfaces of waterprocessing equipment, interfering with the operation of such equipment.For example, heat exchange surfaces in contact with water having mineralsolids dissolved therein can become fouled as mineral scale depositsthereon, interfering with the designed heat transfer characteristics ofthe surface, and rendering a heat exchanger containing such a surfaceless efficient. Mechanical filtration is of limited usefulness inaddressing such problems, as the main cause of scale is typically solidsdissolved in the water, rather than suspended solid particles.

Accordingly, there remains a need in the art for a purification mediathat can provide purification of fluids, such as water, by removingsignificant quantities of contaminants while the purification system isprocessing water at significant flow rates with a low pressure dropacross the purification media. Such a system must be able to processlarge quantities of water without clogging or substantially increasingin pressure drop.

Similarly, there remains a need for a water purification system thatreduces or eliminates scale formation in equipment used to processwater, including water supplied at low input pressures.

In addition to the need for filters that function at low waterpressures, there is a need for purification systems that aresufficiently small that they can be incorporated into the water supplylines in household appliances, such as refrigerators, dishwashers,laundry washers, and the like.

SUMMARY

One or more of the embodiments of the fluid purification materials,media, apparatus, and methods described herein satisfies one or more ofthese needs by providing a rigid porous purification block having arelatively small thickness, and containing at least a porous polymer.Desirably, the porous polymer functions to hold a fluid purificationmaterial, as described below. However, whether a fluid purificationmaterial is present or not, the rigid porous purification block servesto reduce or avoid direct impingement of fluid onto any downstream fluidpurification media, and also to desirably function as a prefilter forsuch downstream fluid purification media by, e.g., mechanical filtrationor size exclusion. The fluid purification media is particularly suitedfor use in purifying liquids, and in particular water. Because of theability of the fluid purification media to remove contaminants, such aschlorine, chloramine, microorganisms such as bacteria and viruses, andparticulates, it is suitable for use in water purification systemsintended to produce potable or drinking water. When carbon is used as afluid purification material with this particular geometry the rigidporous purification block can be used in a purification system that iscapable of removing large amounts of bacteria and other contaminantsfrom water at high flow rates with very low pressure drop.

In one embodiment is disclosed herein a fluid purification media,comprising: a rigid porous purification block, comprising:

a longitudinal first surface;

a longitudinal second surface disposed inside the longitudinal firstsurface; and

a porous high density polymer disposed between the longitudinal firstsurface and the longitudinal second surface;

wherein said porous purification block has an average pore diameter thatranges between 2,000 and 60,000 Å. Desirably, the rigid porouspurification block can further contain a fluid purification material,such as particulate carbon or metal oxides. However, the rigid porouspurification block may be 100% porous polymer material, particularlywhen used in conjunction with a second fluid purification material, suchas a fibrous nonwoven fabric. Such a rigid porous purification block cangenerally have a void volume of 30-70 volume %.

In another embodiment is disclosed herein a carbon material for use inthe purification media, i.e., a fluid purification material comprisingparticles of porous carbon, wherein:

the particles have a porosity of 40-90%, more particularly from 50-90%

In another embodiment is disclosed herein a fluid purification media,comprising:

a fibrous, nonwoven fabric; and

a fluid purification material comprising particles of porous carbonhaving a porosity of 40-90%.

In another embodiment is disclosed herein a purification systemcomprising a combination of the purification media described herein.

In another embodiment is disclosed a purification apparatus comprisingone or more of the purification media described herein.

In another embodiment is disclosed a method of purifying a fluid, suchas water, comprising causing the fluid to flow from an exterior surfaceof the purification media to an interior surface thereof, or conversely.

The carbon material described herein, purification media containing it,and systems containing this purification media, unexpectedly allow forthe use of these materials and devices to purify fluids with anextremely low pressure drop. This, in turn, allows these materials anddevices to remove contaminants from commercially significant volumes offluids, in particular water, under low pressure conditions atcommercially reasonable flow rates.

In particular, the combination of a rigid porous purification block,whether or not containing a fluid purification material, in conjunctionwith a nonwoven, fibrous fabric disposed downstream of the porouspurification block, and more desirably disposed in a manner thatincoming fluid to be treated does not directly impinge on the nonwovenfibrous fabric, has been found to be particularly effective of purifyingwater at low water pressures. Desirably, the nonwoven fibrous fabriccontains a structural fiber, such as microglass fibers, polyolefins(such as polyethylene or polypropylene), polyesters, or the like.Additionally, disposed on, among, or within these structural fibers areparticles or fibers of active materials capable of interacting withmicroorganisms or other impurities with which they came into contact.Examples include alumina particles or fibers, such as nanoscale ormicroscale alumina fibers or particles, aluminum fibers or particles,such as nanoscale or microscale aluminum fibers or particles,aluminosilicate fibers or particles, such as nanoscale or microscalealuminosilicate fibers or particles more particularly microscalealuminum fibers or particles, titanium dioxide particles, zinc oxideparticles, and the like, and combinations of these. While not wishing tobe bound by theory, it is believed that these particles have a zetapotential in water that permits the retention and removal from water orvarious bacteria (e.g. E. coli), viruses, cysts, and other potentialpathogens.

Of particular interest are a nanowoven fibrous fabrics containingmicroscale aluminum fibers or particles, or microscale aluminosilicatefibers, or a combination of these disposed between the structure fibers,whether evenly distributed or in clumps. These aluminum and/oraluminosilicate materials can be combined microscale titanium dioxideand/or zinc oxide. A particularly suitable titanium dioxide is availablecommercially under the tradename P25 (Degussa).

Other suitable active materials include transition metaloxide-aluminosilicate materials described in U.S. Pat. No. 7,288,498(the entire contents of which are incorporated herein by reference), themetal oxide nanoparticles described in U.S. Pat. No. 7,357,868 (theentire contents of which are incorporated herein by reference), and thealuminosilicate described in U.S. Pat. No. 6,241,893 (the entirecontents of which are incorporated herein by reference).

The combination of a rigid porous purification block with a aluminum oraluminosilicate containing pleated nonwoven fabric disposed in thehollow core of the block can, for example, provide 99.99999% reductionof 0.1-5 micron AC dust with only a 10% flow reduction. Commerciallyavailable filters tested experienced a 79-92% flow reduction.

Moreover, the combination of a rigid porous purification block asdescribed herein with a nonwoven fibrous fabric containing an activematerial avoids the need to use expensive silver in the filtrationsystem.

In addition, it has been found that similar beneficial results whetherthe length of the porous purification block is 6 inches or is 3 inches.As a result, the fluid purification systems and apparatus disclosedherein are suitable for incorporation into appliances such asrefrigerators, automatic dishwashers, laundry washers, and otherappliances having a water input line.

BRIEF DESCRIPTION OF DRAWINGS

The purification media, systems and methods described herein can be moreclearly understood by reference to the accompanying drawings, which areintended to be illustrative, and not limiting, of the appended claims.

FIG. 1A is a schematic perspective view of one embodiment of apurification media described herein. FIG. 1B is a schematic top view ofthe purification media of FIG. 1A.

FIG. 2A is a schematic perspective view of another embodiment of apurification media described herein. FIG. 2B is a schematic top view ofthe purification media of FIG. 2A.

FIG. 3 is a schematic side view of another embodiment of a purificationmedia described herein.

FIG. 4 is a graph of cumulative Hg intrusion vs. diameter for anembodiment of porous carbon used in an embodiment of porous purificationblock disclosed herein.

FIG. 5 is a graph of log differential intrusion vs. diameter for theporous carbon of FIG. 4.

FIG. 6 is a graph of differential intrusion vs. diameter for the porouscarbon of FIG. 4.

FIG. 7 is a graph of cumulative pore area vs. diameter for the porouscarbon of FIG. 4.

FIG. 8 is a graph of incremental pore area vs. diameter for the porouscarbon of FIG. 4.

FIG. 9 is a photograph of a test rig for evaluating the ability ofembodiments of the disclosed filtration system to remove scale fromwater.

FIG. 10 is a photograph of the test rig showing scale buildup in theunfiltered side of the testing.

FIG. 11 is an SEM micrograph of an embodiment of nonwoven fibrous fabricdescribed herein.

FIG. 12 is an SEM micrograph showing a magnified portion of the materialof FIG. 11.

FIG. 13 is an EDX spectrum of the material of FIG. 11.

FIG. 14 is an EDX spectrum of a portion of the material shown in FIG.12.

FIG. 15 is a photomicrograph of a mixture of porous carbon and polymeraccording to an embodiment disclosed herein.

FIG. 16 is a magnified portion of the material shown in FIG. 15.

FIG. 17 is a graph of cumulative Hg intrusion vs. pore size for anembodiment of rigid porous purification block disclosed herein.

FIG. 18 is a graph of incremental intrusion vs. pore size for theembodiment of FIG. 17.

FIG. 19 is a graph of cumulative pore area vs. pore size for theembodiment of FIG. 17.

FIG. 20 is a graph of differential intrusion vs. pore size for theembodiment of FIG. 17.

FIG. 21 is a graph of log differential intrusion vs. pore size for theembodiment of FIG. 17.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

As used herein, the term “fluid purification material” refers toparticles having an active role in removing contaminants from fluid,such as the porous carbon particles described in more detail below ormetal oxide nanoparticles, such as zinc oxide, titanium oxide, zirconiumoxide, alumina, aluminosilicates, and the like and combinations thereof.

The term “rigid porous purification block” is used to refer to thestructure formed by combining particles of one or more fluidpurification materials and a binder resin. Such a block has an first, orexterior, longitudinal surface and a second, or interior longitudinalsurface, and a two transverse dimensions perpendicular to thelongitudinal direction. As an example, the rigid porous purificationblock may take the form of a cylindrical annulus, wherein the outersurface of the annulus is the longitudinal first surface and the innersurface of the annulus is the second longitudinal surface, and whereinthe diameter of the outer surface is the first transverse dimension andthe diameter of the inner surface is the second transverse dimension.However, the scope of the term “rigid porous purification block” is notlimited to cylindrical geometry, and other geometries, such as thosehaving an oval, square, or rectangular cross section, are also included.

The term “fluid purification media” is used herein to more generallyrefer to individual structures capable of purifying fluids, such as arigid porous purification block or a nonwoven fabric containing a fluidpurification material disposed thereon.

The term “fluid purification system” is used herein to refer to acombination of two or more fluid purification media, including but notlimited to, a combination of a porous purification block with a nonwovenfabric containing a fluid purification media disposed thereon.

The term “fluid purification apparatus” is used herein to refer to adevice containing a fluid purification media or a fluid purificationsystem, along with the associated housing, fluid inlets and outlets, andother components that enable the device to purify a fluid, e.g., water.

As used herein, the term “structural fiber” refers to fibers thatprovide dimensional stability to the nonwoven fibrous fabric and providesupport to an active material disposed thereon.

As used herein, the term “active material” refers to a material disposedon, among, or in the structural fiber of the nonwoven fibrous fabric,and which participates in the removal or reduction of contaminants inthe fluid being filtered by a mechanism different from size exclusion ormechanical filtration. Examples of such an active material includecarbon particles as described herein, carbon fibers, particles or fibersof alumina, particles or fibers of aluminum, particles or fibers ofmetal oxides, such as titanium oxide, zinc oxide, zirconium oxide,particles or fibers of aluminosilicates and the like, or combinations ofthese.

As used herein, the term “about” when used in connection with anumerical value or range includes somewhat more or somewhat less thanthe numerical value, to a deviation from the numerical value of ±10%.

In one embodiment, the fluid purification material disclosed hereincomprises a particulate carbon, and in particular, a porous particulatecarbon. Desirably, the porous particulate carbon has a porosity of about40 to about 90% by volume, more particularly about 50% to about 90%,more particularly, about 70 to 85%, even more particularly, around 75%,as measured by nitrogen intrusion. Desirably, the average pore diameterranges between 60 Å 20.000 Å. Desirably, the particles have a bulkdensity of 0.4 to 0.9 g/cm³, more particularly, around 0.78 g/cm³.Desirably, the particles have a specific surface area of from 1500 to2000 m²/g, measured by the Brunauer-Emmett-Teller (BET) technique.

A particular suitable carbon was analyzed by Hg intrusion to assess itspore size distribution and other properties, and the results are givenin Table 1. A graph of cumulative intrusion vs. diameter is given inFIG. 4. A graph of log differential intrusion vs. diameter is given inFIG. 5. A graph of differential intrusion vs. diameter is given in FIG.6. A graph of cumulative pore area vs. diameter is given in FIG. 7. Agraph of incremental pore area vs. diameter is given in FIG. 8.

TABLE 1 Summary Report Penetrometer: 389-(10) 5 Bulb, 1.131 Stem, PowderPen. Constant: 21.630 μL/pF Adv. Contact 130.000 degrees Angle: Pen.Weight: 63.6931 g Rec. Contact 130.000 degrees Angle: Stem Volume:1.1310 mL Hg Surface 485.000 dynes/cm Tension: Max. Head 4.4500 psia HgDensity: 13.5335 g/mL Pressure: Pen. Volume: 5.9250 mL Sample 0.3203 gWeight: Assembly 125.4047 g Weight: Low Pressure: Evacuation Pressure:50.000 μmHg Evacuation Time: 5 mins Mercury Filling Pressure: 1.46 psiaEquilibration Time: 10 secs High Pressure: Equilibration Time: 10 secsNo Blank Correction Intrusion Data Summary Total Intrusion Volume =3.5100 mL/g Total Pore Area = 406.678 m²/g Median Pore Diameter (Volume)= 250806 A Median Pore Diameter (Area) = 77 A Average Pore Diameter (4V/A) = 345 A Bulk Density = 0.2306 g/mL Apparent (skeletal) Density =1.2110 g/mL Porosity = 80.9546% Stem Volume Used =      99%**** TabularReport Cumu- lative Cumu- Mean Pore Incremental lative Incremental % ofTotal Diameter Volume Pore Volume Pore Area Pore Area Intrusion (A)(mL/g) (mL/g) (m²/g) (m²/g) Volume 1240882 0.0000 0.0000 0.000 0.0000.0000 1049811 0.0242 0.0242 0.001 0.001 0.6891 719934 0.1248 0.10070.007 0.006 3.5569 510838 0.4092 0.2843 0.029 0.022 11.6570 3824621.1856 0.7765 0.110 0.081 33.7787 289673 1.7237 0.5380 0.184 0.07449.1074 233019 1.9650 0.2413 0.226 0.041 55.9814 191168 2.1124 0.14750.257 0.031 60.1834 154902 2.1966 0.0842 0.278 0.022 62.5817 1255982.2482 0.0516 0.295 0.016 64.0511 101492 2.2870 0.0388 0.310 0.01565.1556 84446 2.3059 0.0190 0.319 0.009 65.6961 75438 2.3159 0.01000.324 0.005 65.9798 66309 2.3345 0.0186 0.335 0.011 66.5102 52497 2.33800.0035 0.338 0.003 66.6085 40420 2.3445 0.0065 0.345 0.006 66.7950 328542.3514 0.0069 0.353 0.008 66.9917 26622 2.3576 0.0062 0.362 0.00967.1681 21561 2.3621 0.0045 0.371 0.008 67.2970 17605 2.3661 0.00390.380 0.009 67.4089 14308 2.3699 0.0038 0.390 0.011 67.5174 11569 2.37400.0042 0.405 0.014 67.6361 9200 2.3777 0.0037 0.421 0.016 67.7412 73462.3812 0.0035 0.440 0.019 67.8396 6008 2.3845 0.0033 0.462 0.022 67.93454466 2.3943 0.0098 0.549 0.087 68.2126 3432 2.3948 0.0005 0.555 0.00668.2262 2841 2.4043 0.0095 0.689 0.134 68.4975 2289 2.4049 0.0006 0.6990.010 68.5145 1909 2.4161 0.0112 0.934 0.235 68.8333 1473 2.4212 0.00511.073 0.139 68.9791 1294 2.4275 0.0063 1.268 0.195 69.1588 1141 2.43360.0061 1.481 0.213 69.3318 1051 2.4358 0.0023 1.567 0.086 69.3962 9662.4450 0.0092 1.946 0.379 69.6573 876 2.4494 0.0044 2.147 0.201 69.7828819 2.4555 0.0061 2.444 0.296 69.9558 765 2.4611 0.0056 2.736 0.29270.1152 722 2.4662 0.0051 3.020 0.284 70.2610 683 2.4724 0.0062 3.3820.363 70.4374 639 2.4808 0.0085 3.912 0.529 70.6782 601 2.4865 0.00574.292 0.380 70.8410 565 2.4972 0.0107 5.051 0.759 71.1462 525 2.50710.0099 5.804 0.753 71.4277 489 2.5191 0.0120 6.788 0.984 71.7702 4562.5307 0.0115 7.802 1.013 72.0991 425 2.5452 0.0145 9.168 1.367 72.5129401 2.5539 0.0087 10.035 0.867 72.7605 383 2.5647 0.0108 11.167 1.13273.0691 366 2.5738 0.0090 12.156 0.989 73.3268 349 2.5874 0.0136 13.7111.555 73.7134 332 2.5987 0.0113 15.073 1.362 74.0356 319 2.6093 0.010616.402 1.330 74.3375 306 2.6218 0.0125 18.037 1.635 74.6936 293 2.63330.0115 19.611 1.574 75.0225 282 2.6453 0.0120 21.315 1.704 75.3651 2722.6558 0.0105 22.854 1.539 75.6635 262 2.6696 0.0138 24.959 2.10576.0569 248 2.6934 0.0238 28.796 3.837 76.7352 232 2.7162 0.0227 32.7113.915 77.3829 218 2.7416 0.0255 37.391 4.680 78.1087 204 2.7650 0.023341.955 4.564 78.7734 195 2.7776 0.0126 44.537 2.582 79.1329 189 2.79150.0139 47.479 2.942 79.5297 182 2.8116 0.0201 51.900 4.421 80.1028 1742.8297 0.0181 56.054 4.155 80.6183 167 2.8505 0.0208 61.050 4.99681.2118 159 2.8710 0.0205 66.189 5.139 81.7951 153 2.8890 0.0180 70.8924.703 82.3072 146 2.9121 0.0231 77.202 6.309 82.9651 140 2.9299 0.017982.293 5.091 83.4738 135 2.9519 0.0219 88.796 6.503 84.0978 130 2.96300.0112 92.230 3.434 84.4166 127 2.9760 0.0130 96.307 4.077 84.7863 1252.9846 0.0086 99.057 2.750 85.0305 122 2.9983 0.0137 103.543 4.48685.4205 118 3.0152 0.0169 109.249 5.706 85.9020 115 3.0262 0.0111113.088 3.839 86.2174 113 3.0397 0.0135 117.860 4.772 86.6007 110 3.05520.0155 123.503 5.643 87.0415 107 3.0680 0.0129 128.319 4.815 87.4078 1053.0779 0.0099 132.098 3.779 87.6893 103 3.0886 0.0107 136.275 4.17787.9945 100 3.1004 0.0118 140.966 4.691 88.3303 98 3.1121 0.0117 145.7104.744 88.6626 97 3.1197 0.0076 148.862 3.153 88.8797 95 3.1330 0.0133154.486 5.624 89.2595 92 3.1504 0.0174 162.031 7.544 89.7546 90 3.16060.0102 166.589 4.559 90.0463 88 3.1737 0.0131 172.546 5.957 90.4194 863.1843 0.0106 177.472 4.926 90.7212 84 3.1965 0.0121 183.235 5.76391.0671 83 3.2067 0.0102 188.193 4.958 91.3588 81 3.2202 0.0135 194.8516.658 91.7420 79 3.2347 0.0145 202.228 7.377 92.1557 77 3.2474 0.0127208.862 6.634 92.5186 75 3.2562 0.0088 213.540 4.678 92.7696 74 3.26840.0121 220.111 6.570 93.1155 73 3.2765 0.0081 224.572 4.461 93.3461 713.2860 0.0095 229.904 5.332 93.6174 70 3.2954 0.0094 235.260 5.35693.8854 69 3.3061 0.0107 241.476 6.215 94.1906 68 3.3163 0.0102 247.5326.057 94.4822 66 3.3252 0.0088 252.838 5.306 94.7332 65 3.3327 0.0075257.425 4.587 94.9469 64 3.3397 0.0070 261.780 4.356 95.1469 63 3.35130.0117 269.160 7.380 95.4793 62 3.3588 0.0075 274.008 4.847 95.6929 613.3665 0.0076 279.020 5.012 95.9100 60 3.3728 0.0063 283.243 4.22496.0897 59 3.3785 0.0057 287.129 3.885 96.2525 58 3.3837 0.0052 290.7443.615 96.4017 57 3.3898 0.0061 295.002 4.259 96.5747 56 3.3946 0.0048298.396 3.394 96.7104 55 3.3998 0.0052 302.188 3.792 96.8596 54 3.40540.0056 306.313 4.125 97.0190 53 3.4096 0.0042 309.435 3.122 97.1377 533.4146 0.0050 313.240 3.805 97.2801 51 3.4209 0.0063 318.148 4.90897.4599 50 3.4259 0.0050 322.125 3.977 97.6023 49 3.4306 0.0048 325.9873.862 97.7380 48 3.4351 0.0045 329.726 3.738 97.8668 47 3.4401 0.0050333.941 4.215 98.0093 46 3.4444 0.0043 337.628 3.687 98.1314 46 3.44880.0044 341.492 3.864 98.2568 45 3.4520 0.0032 344.360 2.868 98.3484 443.4550 0.0030 347.049 2.689 98.4332 43 3.4612 0.0062 352.775 5.72698.6095 42 3.4651 0.0039 356.513 3.738 98.7214 41 3.4686 0.0035 359.8613.348 98.8198 40 3.4723 0.0037 363.506 3.645 98.9249 39 3.4774 0.0051368.698 5.192 99.0708 38 3.4822 0.0048 373.689 4.992 99.2064 37 3.48640.0043 378.322 4.632 99.3285 36 3.4892 0.0027 381.347 3.025 99.4065 353.4950 0.0058 388.011 6.664 99.5727 34 3.4988 0.0038 392.543 4.53399.6812 33 3.5023 0.0035 396.763 4.220 99.7796 32 3.5062 0.0039 401.7144.951 99.8915 31 3.5100 0.0038 406.678 4.963 100.0000

In a particular embodiment, the carbon particles have an averageparticle size in the range of about 10 to 200 μm, more particularly,about 10 to 100 μm. In a particular embodiment, the particles have aparticle size distribution such that 5-25% by weight of the particlesare smaller than 325 mesh and 7% by weight of the particles are largerthan 80 mesh. Desirably, such particles are obtained from a wood-basedcarbon, rather than from a coal based carbon. In some circumstances, acoconut-shell based carbon can be used, although a wood-based carbon ismore desirable for ease of handling and processing. The carbon particlescan be sized by suitable sizing methods and their average size and sizedistribution adjusted by screening and measuring methods known in theart, such as using a laser measurement device, such as a CoulterMultisizer. Sizing and screening can occur before or after theadditional processing described herein.

In a particular embodiment, the additional processing of the particlesincludes acid reacting. More specifically, this can desirably compriseintroducing the particles into a reactor, where they are contacted withstrong phosphoric acid (desirably, 85-99%) under a pressure of 200-300psi for a period of time ranging between 1-4 hours, desirably about 1hour. Following this reaction, the particles are washed with water andtransferred to a furnace for heat treating. Desirably, the particles areheat treated in a furnace in e.g., nitrogen, ammonia, or CO₂ atmosphere,at a temperature ranging between about 700° and 1000° C., moreparticularly between about 700° and 890° C. for a period of time,generally ranging from about 5 to about 24 hours. The result of thisprocessing is carbon particles having a porosity of 50-90%, by volume.The carbon is sufficiently active that one gram can process 470 gallonsof water having a chlorine content of 2 ppm, which is removed from thewater by the carbon. If necessary or desirable, the particles can groundfurther, e.g., in an air jet, in order to adjust their sizecharacteristics.

The carbon particles can then be formed into a rigid porous purificationblock by combination with a porous polymeric binder. In general, it isdesirable to use a carbon loading of about 10-30% by weight, moreparticularly about 15-30% based on the total weight of the porouspurification block. The porous purification block can desirably containfrom about 65 to 90%, more particularly about 70 to 90%, even moreparticularly, about 70-85% by weight of porous polymer, such as highdensity polyethylene (HDPE) polypropylene, or ultra high molecularweight polyethylene (UHMWPE). Desirably, the HDPE can have an averagemolecular weight of around 700,000. Desirably, the porous purificationblock can have average pore sizes ranging between 2,000 and 60,000 Å,more particularly between 10,000 and 60,000 Å. Desirably, the voidvolume of the porous block can be 30-70%, more particularly, about 40%.The porous purification block can be produced by a number of differentprocesses, such as blow molding, extrusion, and the like. Desirably, thepolymeric material of the porous purification block has a micron ratingfrom 10-150.

Additionally or alternatively, the rigid porous purification block cancontain other fluid purification materials in addition to, or in placeof, the carbon particles. These can include, zinc oxide, e.g.,nanoparticulate zinc oxide, ranging from about 0.01 to about 0.1%, moreparticularly about 0.06%, by weight, based on the total weight of theporous purification block. Other suitable fluid purification materialsinclude zeolite particles, zirconia particles, alumina nanofibers (e.g.,in amounts ranging from 2-3% by weight, based on the total weight of theporous purification block), aluminosilicate fibers or particles, and thelike.

For example, a rigid porous purification block can be formed bycombining 80% by weight HDPE and 20% by weight of a combination ofaluminosilicate and nanozinc particles (Alusilnz™, Selecto, Inc.).

In a particular embodiment, the rigid porous purification block can beformed by mixing the fluid purification materials, e.g. the particulatecarbon described above, with particles of porous polymer in a mold ofthe size and shape of the desired porous purification block, and heatingin an oven. Desirably, the particles of porous polymer have an averageparticle size in the range of 10-50 μm, more particularly, 20-40 μm.Desirably, the binder particles have a high porosity relative to theporosity of typical polymeric binders. Porosities of 40-70% aredesirable. The mixture can desirably be heated in the mold for about 45minutes at a temperature of around 400° F.

A micrograph of a suitable material containing 27 wt % porous carbon inporous polymer is given in FIG. 15. A magnified portion of thismicrograph is given in FIG. 16.

The porous purification block can then be allowed to cool and removedfrom the mold. If desired, the outer surface, and in particular, thelongitudinal first surface, of the porous purification block can becoated with a layer of porous polymer, such as a HDPE, desirably thesame or similar HDPE to that used to make the porous purification block.Desirably, such a coating can have a thickness ranging from 1/30 to 1/40of the thickness of the porous purification block.

A particular rigid porous purification block containing 70% HDPE, 29%porous carbon and 1% zinc oxide was analyzed by Hg intrusion to assessits pore size distribution and other properties. The results are givenin Table 2 below, and graphs showing cumulative Hg intrusion,incremental intrusion, cumulative pore area, differential intrusion, andlog differential intrusion, each as a function of pore size, are givenin FIG. 17 to FIG. 21, respectively.

TABLE 2 Summary Report Penetrometer parameters Penetrometer: 674-(24) 15Bulb, 3.263 Stem, Solid Pen. Constant: 32.477 μL/pF Pen. Weight: 74.9934g Stem Volume: 3.2630 mL Max. Head 4.4500 psia Pressure: Pen. Volume:17.7011 mL Assembly 295.6950 g Weight: Hg Parameters Adv. Contact130.000 degrees Rec. Contact 130.000 degrees Angle: Angle: Hg Surface485.000 dynes/cm Hg Density: 13.5335 g/mL Tension: Low Pressure:Evacuation Pressure: 50 μmHg Evacuation Time: 5 mins Mercury FillingPressure: 0.52 psia Equilibration Time: 10 secs High Pressure:Equilibration Time: 10 secs No Blank Correction Intrusion Data SummaryTotal Intrusion Volume = 1.4145 mL/g Total Pore Area = 122.459 m²/gMedian Pore Diameter (Volume) = 29.8983 μm Median Pore Diameter (Area) =0.0056 μm Average Pore Diameter (4 V/A) = 0.0462 μm Bulk Density at 0.52psia = 0.4373 g/mL Apparent (skeletal) Density = 1.1467 g/mL Porosity =61.8609% Stem Volume Used =    27% Tabular Report Cumu- lative Cumu-Pore Pore Incremental lative Incremental Pressure Diameter Volume PoreVolume Pore Area Pore Area (psia) (μm) (mL/g) (mL/g) (m²/g) (m²/g) 0.52345.2103 0.0000 0.0000 0.000 0.000 0.75 239.7468 0.0209 0.0209 0.0000.000 1.00 180.6952 0.0344 0.0135 0.001 0.000 2.00 90.4928 0.0638 0.02940.001 0.001 2.99 60.4679 0.0796 0.0159 0.002 0.001 3.99 45.3138 0.09530.0157 0.003 0.001 5.49 32.9469 0.5164 0.4211 0.046 0.043 6.99 25.88930.9506 0.4343 0.106 0.059 8.48 21.3271 0.9995 0.0488 0.114 0.008 10.4817.2563 1.0622 0.0627 0.127 0.013 12.97 13.9415 1.0956 0.0334 0.1350.009 15.96 11.3322 1.1179 0.0223 0.142 0.007 19.99 9.0458 1.1343 0.01640.149 0.006 23.00 7.8651 1.1420 0.0077 0.152 0.004 24.99 7.2376 1.14630.0043 0.155 0.002 29.97 6.0346 1.1546 0.0083 0.160 0.005 37.19 4.86291.1607 0.0061 0.164 0.004 46.73 3.8703 1.1649 0.0042 0.168 0.004 56.563.1979 1.1674 0.0026 0.171 0.003 71.56 2.5273 1.1701 0.0026 0.175 0.00486.84 2.0827 1.1718 0.0018 0.178 0.003 111.77 1.6182 1.1732 0.0014 0.1810.003 136.32 1.3268 1.1744 0.0012 0.184 0.003 172.04 1.0513 1.17570.0012 0.188 0.004 216.71 0.8346 1.1766 0.0009 0.192 0.004 266.17 0.67951.1773 0.0008 0.196 0.004 326.16 0.5545 1.1780 0.0007 0.201 0.005 416.990.4337 1.1790 0.0009 0.208 0.007 517.43 0.3495 1.1795 0.0005 0.213 0.005636.69 0.2841 1.1804 0.0009 0.225 0.012 697.71 0.2592 1.1807 0.00030.230 0.005 797.38 0.2268 1.1812 0.0005 0.238 0.008 988.74 0.1829 1.18180.0006 0.250 0.012 1196.07 0.1512 1.1831 0.0013 0.281 0.031 1297.770.1394 1.1837 0.0005 0.296 0.015 1394.85 0.1297 1.1838 0.0001 0.2980.003 1496.36 0.1209 1.1843 0.0006 0.317 0.018 1595.88 0.1133 1.18500.0006 0.339 0.022 1697.96 0.1065 1.1854 0.0004 0.353 0.014 1895.420.0954 1.1861 0.0007 0.382 0.030 2043.26 0.0885 1.1865 0.0004 0.4010.018 2194.29 0.0824 1.1875 0.0010 0.446 0.045 2345.37 0.0771 1.18820.0007 0.482 0.037 2493.60 0.0725 1.1890 0.0008 0.525 0.042 2643.820.0684 1.1894 0.0003 0.544 0.020 2693.72 0.0671 1.1896 0.0002 0.5580.014 2843.87 0.0636 1.1905 0.0009 0.615 0.057 2993.85 0.0604 1.19130.0008 0.666 0.051 3241.79 0.0558 1.1929 0.0016 0.778 0.112 3492.390.0518 1.1932 0.0003 0.798 0.020 3741.54 0.0483 1.1939 0.0007 0.8520.054 3991.53 0.0453 1.1956 0.0017 0.996 0.144 4240.89 0.0426 1.19710.0016 1.137 0.141 4485.04 0.0403 1.1976 0.0005 1.185 0.048 4725.800.0383 1.1979 0.0003 1.217 0.032 4984.19 0.0363 1.1998 0.0018 1.4130.195 5282.39 0.0342 1.2016 0.0019 1.625 0.213 5481.95 0.0330 1.20290.0013 1.780 0.155 5729.80 0.0316 1.2035 0.0005 1.847 0.067 5982.280.0302 1.2050 0.0016 2.049 0.202 6229.87 0.0290 1.2069 0.0019 2.3050.256 6481.35 0.0279 1.2083 0.0013 2.493 0.188 6729.38 0.0269 1.20950.0013 2.678 0.185 6978.08 0.0259 1.2105 0.0010 2.827 0.149 7474.020.0242 1.2133 0.0028 3.279 0.451 7974.09 0.0227 1.2170 0.0036 3.9000.622 8473.08 0.0213 1.2182 0.0012 4.119 0.219 8973.45 0.0202 1.22140.0032 4.730 0.611 9269.06 0.0195 1.2235 0.0021 5.155 0.425 9568.180.0189 1.2264 0.0029 5.763 0.608 10019.11 0.0181 1.2292 0.0028 6.3640.601 10470.62 0.0173 1.2296 0.0005 6.466 0.102 10971.89 0.0165 1.23310.0035 7.294 0.829 11472.29 0.0158 1.2367 0.0036 8.176 0.882 11970.910.0151 1.2410 0.0043 9.291 1.114 12570.40 0.0144 1.2447 0.0038 10.3141.023 13070.53 0.0138 1.2452 0.0005 10.450 0.136 13617.65 0.0133 1.25010.0049 11.889 1.440 13967.05 0.0129 1.2531 0.0030 12.809 0.920 14307.460.0126 1.2552 0.0021 13.455 0.646 14564.78 0.0124 1.2576 0.0024 14.2230.768 14965.73 0.0121 1.2599 0.0023 14.988 0.765 15416.40 0.0117 1.26390.0040 16.335 1.347 15762.45 0.0115 1.2676 0.0036 17.591 1.256 16166.730.0112 1.2677 0.0001 17.630 0.040 16616.37 0.0109 1.2719 0.0042 19.1501.520 16960.61 0.0107 1.2749 0.0030 20.256 1.106 17316.25 0.0104 1.27720.0024 21.148 0.892 17658.98 0.0102 1.2804 0.0032 22.385 1.237 18064.600.0100 1.2827 0.0023 23.299 0.914 18414.55 0.0098 1.2841 0.0014 23.8660.567 18763.78 0.0096 1.2864 0.0023 24.796 0.930 19163.00 0.0094 1.28890.0025 25.837 1.041 19768.88 0.0091 1.2928 0.0039 27.536 1.699 20268.770.0089 1.2964 0.0036 29.119 1.583 20774.96 0.0087 1.3011 0.0047 31.2312.112 21176.47 0.0085 1.3028 0.0017 32.042 0.812 21628.88 0.0084 1.30310.0003 32.196 0.153 22030.61 0.0082 1.3036 0.0005 32.444 0.248 22635.760.0080 1.3073 0.0036 34.232 1.788 23184.23 0.0078 1.3104 0.0032 35.8341.601 23735.82 0.0076 1.3136 0.0032 37.485 1.652 24086.30 0.0075 1.31570.0021 38.614 1.129 24635.92 0.0073 1.3192 0.0035 40.477 1.863 25038.560.0072 1.3203 0.0011 41.100 0.622 25438.75 0.0071 1.3222 0.0018 42.1291.030 25889.44 0.0070 1.3257 0.0035 44.102 1.973 26440.48 0.0068 1.32940.0037 46.255 2.152 26940.73 0.0067 1.3301 0.0007 46.691 0.436 27390.600.0066 1.3307 0.0006 47.033 0.342 27790.95 0.0065 1.3311 0.0004 47.2950.262 28242.92 0.0064 1.3332 0.0020 48.564 1.269 28992.09 0.0062 1.33550.0023 50.026 1.462 29490.74 0.0061 1.3400 0.0045 52.952 2.927 29992.660.0060 1.3413 0.0013 53.798 0.846 30442.34 0.0059 1.3424 0.0011 54.5350.736 30892.54 0.0059 1.3453 0.0029 56.483 1.948 31293.56 0.0058 1.34710.0019 57.773 1.291 31792.98 0.0057 1.3489 0.0018 59.027 1.254 32342.580.0056 1.3522 0.0033 61.337 2.310 32894.12 0.0055 1.3539 0.0018 62.6051.267 33493.07 0.0054 1.3579 0.0040 65.504 2.900 33994.23 0.0053 1.36880.0109 73.617 8.113 34643.81 0.0052 1.3688 0.0000 73.617 0.000 35494.020.0051 1.3688 0.0000 73.617 0.000 36194.18 0.0050 1.3688 0.0000 73.6170.000 36989.66 0.0049 1.3698 0.0010 74.409 0.793 37640.79 0.0048 1.36980.0000 74.409 0.000 38444.35 0.0047 1.3698 0.0000 74.409 0.000 39188.360.0046 1.3698 0.0000 74.423 0.014 39990.17 0.0045 1.3698 0.0001 74.4690.047 40487.10 0.0045 1.3699 0.0001 74.528 0.059 40992.49 0.0044 1.37170.0018 76.191 1.663 42479.49 0.0043 1.3794 0.0077 83.312 7.121 43333.890.0042 1.3812 0.0018 84.987 1.675 43969.05 0.0041 1.3843 0.0031 88.0133.027 44978.84 0.0040 1.3868 0.0025 90.425 2.411 46471.49 0.0039 1.39080.0040 94.492 4.067 47963.72 0.0038 1.3944 0.0035 98.174 3.683 49463.290.0037 1.3966 0.0022 100.551 2.377 50163.30 0.0036 1.3966 0.0000 100.5510.000 52960.51 0.0034 1.4019 0.0053 106.631 6.079 54462.78 0.0033 1.40660.0047 112.167 5.537 55961.25 0.0032 1.4069 0.0003 112.540 0.37257963.79 0.0031 1.4069 0.0000 112.540 0.000 59960.48 0.0030 1.41450.0076 122.459 9.919

The porous purification block geometry is desirably such that the ratioof the first transverse dimension to the second transverse dimension isbetween 1.2 and 1.9, more particularly between 1.3 and 1.5, even moreparticularly between 1.36 and 1.5. For example, using a cylindricalannular geometry as a nonlimiting example, the ratio for a porouspurification block having an inside diameter of 0.75 inches and anoutside diameter of 1 inch would be 1.33. The ratio for a similar blockhaving an inside diameter of 1.1 inches and an outside diameter of 1.5inches would be 1.36. The ratio for a similar block having an insidediameter of 3 inches and an outside diameter of 4.5 inches would be 1.5.A suitable length (longitudinal dimension) for a cylindrical annulargeometry would be about 6 inches. However, other dimensions for theporous purification block may be used, provided that the ratio oftransverse dimensions is within the ranges set forth above.

The porous purification block described herein can be used alone as thefluid purification media in a fluid purification apparatus byintroducing the porous purification block into a suitable housingcontaining a suitable inlet and outlet manifold that distributesincoming water to be treated (for example) to the first longitudinalsurface of the porous purification block. The water flows along thissurface and radially inward, where it leaves the porous purificationblock at the second longitudinal surface. The fluid spaces around thesetwo surfaces should be separated from each other and not be in fluidcommunication except through the material of the porous purificationblock, as is known in the art, so that the fluid is forced to passthrough the porous purification block by radial flow. Alternatively, ifdesired, water can be introduced into the annular space inside thesecond longitudinal surface and forced to flow radially outward throughthe porous purification block, although this is not the normalcommercial configuration.

In another embodiment, the porous purification block described above canbe combined with a second fluid purification media to form a fluidpurification system, as described herein. For example, a fibrousnonwoven fabric, desirably containing one or more active materialsdisposed thereon, can be combined with the porous purification blockdescribed above. Desirably, this fibrous nonwoven fabric can be disposedin the space defined by the longitudinal second surface. Suitablenonwoven fabric materials include those having structural fibers, e.g.,microglass, polyolefin fibers (such as polyethylene or polypropylene),polyester, or other fibers suitable for formation into a nonwovenfabric. The nonwoven fabric can have one or more active materialsdisposed on, in, among, or between the fibers. The active materials canbe evenly distributed across one or more dimensions of the fabric, orcan be clumped together in one or more regions of higher concentrationof active material.

Desirably, the active material can include particles or fibers ofaluminum, alumina, aluminosilicate, titanium dioxide, zinc oxide,zirconium oxide and the like, and combinations thereof. Desirably, amixture of aluminum fibers or particles (having an average particle sizeor fiber thickness ranging from 4-6 μm, with around 25% of the particlesor fibers having a size below 4 μm), and 0.2-1% of titanium dioxide(P25, Degussa) or zinc oxide or both.

Examples of suitable nonwoven materials include those described in U.S.Pat. Nos. 6,838,005; 7,311,752; 7,390,343; and 7,601,262, the entirecontents of each of which are incorporated herein by reference.

In an embodiment, the fibrous nonwoven fabric can contain micron-sizedaluminum fibers or particles bonded to, or deposited on or among,microglass fibers to produce a nonwoven fabric having a pore size ofapproximately 2 microns, with the largest pores about seven microns. Thelarge pore size results in a low pressure drop while also allowingaccess to submicron particles, rather than having them accumulate on thesurface in a filter bed.

Although the pore size of the nonwoven fabric is 2 microns, it isfunctionally rated at 0.03 microns. The fabric is able to efficientlyfilter particles having sizes from 0.001 to 7 microns. The filters havehigh retention for micron size silica dust, bacteria, virus, DNA/RNA,tannin and latex spheres.

Fibers of active material containing aluminum (either in metallic form,as alumina, or as an aluminosilicate) that are, on average, twonanometers in diameter are produced in a wet process where aluminumpowder is reacted in the chemical process of forming non-woven material.The aluminum fibers attach themselves to the glass fibers in thereaction and during the drying process. They are tens to hundreds ofnanometers long and are heavily aggregated. Most of the measured surfacearea (300-500 m²/g) is on the fibers' external surface.

Aggregates of fibers of active material can increase pressure drop, sothey are controlled by limiting the ratio of aluminum to microglass. Theresult is a flow rate capacity tens to hundreds of times greater thanmembranes. For instance, a 1.5 millimeter thick aluminum-microglassfiber composite can sustain a flow velocity of 1.5 cm/sec (5.4 L/cm2/hr)at 0.7 bar. In water, zeta potential is developed very close to thesurface of a solid, caused by the charge distribution on the surface. Ascompared to a pure microglass media that is electronegative (−35 mV),the microglass/aluminum mixture becomes highly electropositive when thealuminum exceeds 15 weight percent. It is then capable of adsorbing >6LRV (log retention value) of MS2 virus (a bacteriophage). The preferredratio of aluminum to microglass (0.6 μm) is 4:6. Beyond that ratio,aluminum fibers or particles can somewhat aggregate in the pores of thefilter causing an increase in pressure drop. Additional fibers includingcellulose and a polymeric fiber are added to increase flexibility andstrength so that the media can be pleated. Zeta potential for anembodiment of nonwoven fabric described herein is given in Table 3below.

TABLE 3 Zeta potential of nano alumina/microglass Nano alumina content,wt-% Zeta potential, mV ph 0.79 +53 7.18

Another example of a suitable material is sold under the trademarkDISRUPTOR® (Ahlstrom). The nonwoven fabric can desirably have athickness ranging from 0.2 to 1.5 mm, more particularly, about 0.8 mm,and can be folded into a series of pleats and inserted into the spacedefined by the longitudinal second surface. Desirably, the second fluidpurification media does not add significantly to the overall pressuredrop of the fluid purification system.

Yet another example of a nonwoven fibrous fabric for use herein is thatmade by dissolving Alcan hydrate aluminum H10 in a 50% solution ofsodium hydroxide at a temperature of around 300° F. at high pressure.The dissolution is continued until a concentration of 8 lb Al per gallonof solution is obtained. This is diluted at a dilution ratio of 3:1 with3% fumed TiO₂. The resulting mixture is added to a fiber glass slurrypaper (e.g. the commercially available fiber glass slurry paper fromLydle). The resulting precipitate on the paper has particles havingdiameters in the range of 20 nm. Similar nonwoven fabrics can be made bydissolving Alusil™ (Selecto, Inc.) and following a similar process.Other aluminum powders that can be used in a similar process includehigh purity aluminum powders commercially available from ALCOA,including those having standard fine powder grades of ALCOA, includingthose having standard fine powder grades of 4 μm, 5 μm, 6 μm, 7 μm, and9 μm, and standard coarse powder grades of 123, 101, 104, 120, 130,1221, 12C, and 718, or combinations of these.

A section of sample of a nonwoven fibrous fabric having aluminosilicateparticles and fibers on a microglass support fabric was subjected to EDXanalysis in an analytical SEM operating at 20 keV. A backscatteredelectron SEM micrograph of the material is provided in FIG. 11, showingnonwoven fibers with clumps of other material present. FIG. 12 shows oneof these clumps at higher magnification. FIG. 13 shows an EDX spectrumof the overall material, semiquartilative analysis shows the followingelements, in wt %;

C 80 O 18 Al 0.5 Si 0.3 S bdl¹ K 0.1 Ca 0.1 Ti 0.1 Zn 0.3² ¹bdl = belowdetection level. ²May include sodium.

FIG. 14 shows an EDX spectrum for a clump region, showing a large amountof aluminum.

Desirably, each pleat of the nonwoven fabric is V-shaped, wherein oneleg of the V has a length ranging from 6-18 mm, more particularly, from7-10 mm. In general, the smaller pleats (which are therefore present inlarger numbers inside the central opening of the porous purificationblock) provide decreased vibration when compared to larger, lessnumerous pleats.

In another embodiment, the fibrous nonwoven fabric can contain particlesof the carbon fluid purification material described above. In aparticular embodiment, these particles can be loaded onto the nonwovenfabric in an amount ranging between 10 and 30% by weight, moreparticularly around 15% by weight, based on the weight of the secondfluid purification material. This material can be used as is (i.e., asthe only fluid purification media in a fluid purification apparatus), oras part of a fluid purification system in combination with the porouspurification block described above.

Without wishing to be bound by theory, it is believed that the pleatingof the nonwoven fibrous fabric significantly affects the practicalusability of the nonwoven material, especially in combination with arigid porous purification block wherein the pleated fabric is deployedon the inside surface of the rigid annular porous purification block. Inthis regard, a flat sheet of Ahlstrom Disruptor 21944-344 material waswrapped around a rigid porous carbon block rated at 1 micron and anothersuch block rated at 0.6 micron. The resulting filtration systems werechallenged with water containing 123 000 counts of E. Coli per ml at aninitial flow rate of 0.45 gal/min. After 20 L of water had passed thefilter, the pressure drop was at 96%, with flow effectively stopping. Bycontrast, when the same specification rigid porous blocks are testedusing pleated sheets of the same nonwoven material disposed inside theannual opening of the rigid porous block, at an initial flow rate of0.56 gal/min of the same challenge water, a flow rate of 0.51 gal/minwas maintained after 200 L of water had been processed.

In addition, a comparison of the pleated nonwoven fabric without therigid, porous purification block indicated that the fabric wasconsiderably less effective at removing cysts from water. A piece ofpleated Ahstrom Disruptor material was subjected to cyst testing usingNSF 53 as the test protocol. The pleated material alone only provided an87% reduction (a reduction of 99.95% is considered acceptable). When thepleated material is disposed inside the annular opening of a rigidporous purification block as described herein, a reduction of 99.99% orbetter is obtained. Without wishing to be bound by theory, it isbelieved that the absence of the rigid porous purification block allowswater impingement on the pleated fabric to separate and/or break thenonwoven fabric.

When a combination of the porous purification block and a pleatednonwoven fibrous fabric are used, it is generally desirable that thepleated nonwoven fibrous fabric be disposed inside the central openingof the annular tube formed by the porous purification block, asdescribed herein. In such circumstances, it is desirable that thethickness of the annular shell formed by the porous purification blockand the thickness of the nonwoven fibrous fabric be at least 4.5 to 1,more desirably, at least 7 to 1, even more desirably, at least 8.75to 1. For example, it is desirable that, if the nonwoven fibrous fabrichas a thickness of 1 mm, the porous purification block have a thicknessof at least 7 mm.

In order to further show the advantages of using the pleated nonwovenfibrous fabric having an active material disposed therein and disposedon the inner surface of an annular rigid porous purification block, thefollowing tests were conducted:

-   Cyst testing NSF 53 life cyst with AC dust

EXPERIMENT 1

A pleated Ahlstrom Disruptor fabric having 37 pleats each having a 0.25inch length was rolled into a cylinder having a 4.5 inch diameter and a10 inch length was introduced into a radial flow housing. The system wassubjected to challenge water according to NSF testing protocol 53 forlive cyst with AC dust. At a flow rate of 5 GPM, the following resultswere obtained:

-   25% cycle—99.999% reduction-   50% cycle—98% reduction-   75% cycle—91% reduction

EXPERIMENT 2

The same pleated filter as described in Experiment 1 was inserted intothe center of an annular rigid porous polymeric purification blockhaving a thickness of 17 mm and made from high porosity, high molecularweight HDPE. The resulting assembly was inserted into a radial flowhousing and subjected to the same NSF testing protocol. At a flow rateof 5 GPM the following results were obtained:

-   25% cycle—99.999% reduction-   50% cycle—99.999% reduction-   75% cycle—99.999% reduction

EXPERIMENT 3

The same pleated filter as described above but having 17 pleats eachhaving a length of 12 mm was formed into a cylinder having a diameter of1.5 inch and a length of 20 inches and introduced into a radial flowhousing. The assembly was subjected to the same NSF testing protocol. Ata flow rate of 2 GPM the following results were obtained:

-   25% cycle—99% reduction-   50% cycle—97% reduction-   75% cycle—86% reduction

EXPERIMENT 4

The same pleated filter as described in Experiment 3 was inserted intothe center of an annular rigid porous polymeric purification blockhaving a thickness of 16 mm and made from high porosity, high molecularweight HDPE. The thickness of the nonwoven fabric was measured to be 1.5mm. The resulting assembly was inserted into a radial flow housing andsubjected to the same NSF testing protocol. The following results wereobtained at a flow rate of 3 GPM:

-   25% cycle—99.999%-   50% cycle—99.999%-   75% cycle—99.999%

EXPERIMENT 5

The same filter arrangement as in Experiment 4 was used, except theporous purification block contained 61 wt % porous plastic and 30 wt %of a mixture of porous carbon with nanoparticulate zinc to make a rigidpurification block having a thickness of 17 mm. The thickness of thenonwoven fabric was measured to be 1.5 mm. The assembly was introducedinto a radial flow housing and subjected to the same NSF testingprotocol as described above. At a flow rate of 5 GPM, the followingresults were obtained:

-   25% cycle—99.999%-   50% cycle—99.999%-   75% cycle—99.999%

EXPERIMENT 6

The same pleated filter as in Experiment 1 was introduced into thecentral opening of an annular rigid porous polypropylene blow moldedblock having a thickness of 19 mm thickness. The thickness of thenonwoven fabric was measured to be 1.5 mm. The assembly was placed in aradial flow housing and subjected to the same NSF test protocol asdescribed above. At a flow rate of 3 GPM, the following results wereobtained:

-   25% cycle—99.99%-   50% cycle—99.99%-   75% cycle—99.99%

These results indicate that much improved filtration results areobtained when the nonwoven fabric filter is disposed within the annularopening of a rigid porous polymeric purification block, as describedherein.

When a rigid porous purification block is configured as a cylindricalannular porous purification block having 1 inch outer diameter and ¾inch inner diameter and 6 inches in length and incorporated with apleated layer of nonwoven fabric containing microstructural glass fibersand micron-sized aluminum fibers disposed in clumps (DISRUPTOR®,Ahlstrom) having about 19 pleats, the resulting fluid purificationsystem can be incorporated into a fluid purification apparatus and usedto purify challenge water containing chlorine, E. coli, and virusparticles. The purification system was able to remove 2 ppm chlorine,and attain 99.9999% E. coli reduction and 99.99% virus reduction for1000 gallons of water flowing at 1500 cm³/min and at 10 psi.

In order to provide a clearer understanding of the fluid purificationmaterials and system described herein, they are described below withrespect to the drawings, which are not intended to limit the scope ofthe appended claims. Unless indicated otherwise, similar structure inmultiple figures is given the same reference numeral.

FIGS. 1A and 1B provide schematic perspective and top views,respectively, of an embodiment of a cylindrical annular porouspurification block 100 described herein. The porous purification blockhas a longitudinal first surface 102 and a longitudinal second surface104 disposed inside the longitudinal first surface 102, Between thesetwo surfaces is a porous solid material 106, which contains a fluidpurification material, such as porous carbon, and a porous polymericbinder. The cylindrical annulus surrounds a central space 108, which canbe used as a fluid inlet or outlet space (if the porous purificationblock is the only fluid purification media) or to hold additional fluidpurification media therein. The longitudinal first surface has a firsttransverse dimension d1 and the longitudinal second surface has a secondtransverse dimension d2. Desirably, the ratio of d1/d2 is between 1.2and 1.9, more particularly between 1.3 and 1.5, even more particularlybetween 1.36 and 1.5. As an exemplary embodiment, the length of therigid porous purification block can be around 6 inches, the outerdiameter can be around 1.5 inches, and the inner diameter can be around1.0 inch.

FIGS. 2A and 2B provide schematic perspective and top views,respectively, of an embodiment of a fluid purification system 200described herein. The fluid purification system 200 contains a porouspurification block 100, and a pleated nonwoven fabric fluid purificationmedium 110 disposed in central space 108.

FIG. 3 is a schematic side view of another embodiment of a second fluidpurification media disclosed herein, namely a nonwoven fabric 310containing a fluid purification material (e.g., the porous carbondisclosed herein) within the nonwoven fabric.

In order to further illustrate the advantages of the fluid purificationmedia disclosed herein, and in particular of the combination of porouspurification block and nonwoven fabric (Ahlstrom Disruptor) forming thefluid purification system described herein, the following experimentswere conducted. The filters were evaluated to determine on their abilityto remove bacteria (E. Coli), and on their filtration capacity. Inaddition, the micron rating of each filter was evaluated using AC dust(0.1-5 micron) and laser counting.

In testing the flow rate characteristics, flow of 65° F. DI water having100,000 count of bacteria (E. Coli) per cc was initiated through newfilters, and the flow rate measured over the first minute. The resultsare given in Table 4 below. Flow was conducted at a water pressure of12-14 psi,

TABLE 4 Flow rate No. Filter cm³/min 1 KX MB filter 6 × 1.5 inch 375 2Ceramic filter 6 × 2 in 121 3 High porosity carbon block (0.5 micronrated; 236 80% carbon, 20% UHDPE) 4 Carbon block (37.67 mm OD, 26 mm ID,5.8 mm 2560 thickness) and pleated center core (1 mm thickness, pleatinglength 7 mm) of microglass fibers and aluminum-coating active material

In testing for bacterial reduction, water at 13 psi and having anaverage E. Coli count of 30,000 to 100,000 per cc was caused to flowthrough each of the filters in Table 1. The micron ratings of thesefilters is given below, in Table 5 as well as the flow results.

TABLE 5 No. Flow Results Micron Rating 1 No water flow after 7 gallons0.1 2 No water flow after 16 gallons 0.01 3 No water flow after 15gallons 0.1 4 After 200 gallons, water flow rate was 1780 1-2 cm³/minwith 99.9999 bacteria reduction

In addition, further testing confirmed the advantages of filter no. 4 ascompared to the individual components thereof (i.e. the porous carbonblock and the fibrous, nonwoven fabric, considered separately). Theporous carbon block (6×1.25 inches, 8 mm thick) containing 70% UHDPEpolymer, 1% nano zinc, and 29% high porosity carbon (10-200 micron)provided reduction of E. Coli of 0.75 log, and a reduction of viruses of1 log. When a block of the same porous carbon was combined with apleated nonwoven fabric containing aluminum particles placed in itscenter opening Ahlstrom Disruptor, it reduced E. Coli by 99.99999% andreduced viruses by 99.99%. The pleated nonwoven fabric itself reduced E.Coli by 99.99% and reduced viruses by 99.9%.

The filtration system including the combination of porous carbon blockand pleated nonwoven fabric containing an aluminum active material inthe central opening of the carbon block, so that water passes firstthrough a relatively thin carbon block and then through the pleatednonwoven fabric, provides unexpectedly high capacities and flow rates atlow water pressures, such as those found in developing countries andemerging economies. Moreover, the filtration system providesunexpectedly high bacteria reduction when compared to the individualcomponents thereof, as well as when compared to competing products, allof which have much smaller micron ratings. The filtration system isparticularly suited for use in emerging economies and developingcountries because it allows for a large volume of water to be processed,unlike competing products, which shut down in the presence of algae ororganics in the water.

The filtration system disclosed herein also provides enhanced turbidityreduction when compared to other systems. For example, in turbiditytesting done according to NSF 53 at 15 psi, the KX filter noted abovewas unable to provide flow when challenged with incoming water having aturbidity of 11 NTU. By contrast, the purification system describedherein having a thin carbon block and a pleated nonwoven fabric reducedthe turbidity from 11 NTU to 0 NTU while providng 1760 cm³ flow rate ofefficient water.

The filtration system described herein can also be used to reducechlorine present in the water being purified. The arrangement of therigid porous purification block and the active material-containingnonwoven fibrous fabric disposed on an inner surface thereof cansignificantly reduce the amount of carbon needed in the purificationblock to reduce chlorine. For example, an annular cylindrical rigidporous purification block having a length of 6 inches, an outer diameterof 1.25 inches and an inner diameter of 1 inch was made from 70 wt %high molecular weigh high density polyethylene and 30 wt % hollow carbonhaving a particle size ranging from 10-160 micron. The total weight ofthe rigid porous block was 36 grams, and 8.78 grams of carbon was used.In the center of the annular block was inserted a pleatedaluminum-containing nonwoven fibrous fabric (Ahlstrom Disruptor). Thechlorine reduction ability of the filter was determined by subjectingthe filter to challenge water containing 2.23 ppm at a flow rate of 0.5GPM over a total capacity of 300 gallons. The resulting chlorinereduction after 300 gallons was measured to be 99%. When the test wasrepeated with a porous block made from coconut shell carbon, thechlorine reduction at 300 gallons was 23%.

Embodiments of the fluid purification media described herein can providethe bacterial reduction of a submicron rated filter while providing apressure drop found with filters having a micron rating of higherthan 1. For example, a new commercially available filter having a micronrating of 1.2 provides a pressure drop of 45%, but provide a reductionof only 67% of challenge bacteria. A new commercially available filterhaving a 0.45 micron rating provides an increased pressure drop (76%),but only a slightly increased reduction in bacteria (72% reduction). Anew commercially available filter having a 0.1 micron rating provides aneven larger pressure drop (99%) and achieves bacterial reduction of99.99%. A new commercially available filter having a micron rating of0.027 provides a pressure drop of 99.99% to achieve a bacteria reductionof 99.9999%. All of these tests were conducted according to NSF testprotocol P231 at an inlet pressure of 60 psi. It is clear that existingcommercially available filters achieve acceptable bacterial reductiononly at very large pressure drops, rendering them unsuitable for lowwater pressure installations. Moreover, none of the tested commerciallyavailable filters provided any noticeable degree of scale control.

By contrast, the filtration system described herein has an overallmicron rating of 2, yet provides only a 2% pressure drop while achievinga bacterial reduction of 99.9999% using the same test protocol. Becauseof this combination of low pressure drop and high bacterial reduction,the filtration system disclosed herein is ideally suited for use in lowwater pressure environments such as emerging economies and developingcountries without highly developed water supply infrastructure.Moreover, the filtration system described herein provides scale controlon the order of 98%.

As further indication of the bacteria-removing capabilities of thedisclosed filtration system, the following testing of an embodiment of afiltration system disclosed herein was conducted. The testing wasconducted according to NSP P231 at 15 psi inlet water. The rigid porouspurification block was a cylindrical annular block having an outerdiameter of 1.45 inch, an inner diameter of 1 inch, a length of 6inches, and contained 28% porous carbon, 70% HDPE, and 2%nanoparticulate zinc oxide. The nonwoven fibrous fabric was a microglassnonwoven fabric having aluminum or aluminosilicate particles disposedthereon, and having a 1 mm thickness with 23 pleats, disposed in thecentral opening of the rigid porous purification block.

EXPERIMENT A

Cycle: 10 min ON and 10 min OFF Inlet Pressure: 15 psi Flow: 0.3 GPM(1.13 L/min) Sampling Effluent: every cycle at Influent: 1^(st) cycleand last Points: middle cycle First Run: 50 liters (actual run 16 100%reduction (5 gallons of 10,250 counts/mL samples) Second Run: 75 litersDI city water 100% reduction (6 2 hrs 10 min samples) Third Run: 10liters (actual 4 gallons 100% reduction (1 of 11,400 counts E. coli/sample) mL) Fourth Run: 50 liters (actual 16 100% reduction (5 gallonsof E. coli at samples) 11,000 counts/mL)

EXPERIMENT B

Influent Effluent Log (cfu/100 mL) (cfu/100 mL) Reduction BacteriaFilter E. Coli Results First Cycle 3.7 × 10⁷ <1.0 >7.6  50 L 2.7 × 10⁷<1.0 >7.4 100 L 5.5 × 10⁷ <1.0 >7.7 Bacteria Filter MS2 Phage ResultsFirst Cycle 9.1 × 10⁵ <1.0 >5.9  50 L 8.9 × 10⁵ <1.0 >5.9 100 L 1.7 ×10⁶ <1.0 >6.2

EXPERIMENT C

Inlet: 30 NTU Inlet Pressure: 15 PSI Flow at sample point: 0.3 GPMBacteria Reduction Cycle with AC dust 100% reduction Bacteria ReductionCycle with AC dust 100% reduction Total water run with bacteria 260liters Conclusion: Filter with 30 NTU at cycle point reduced bacteriawith AC dust 100% per NSF protocol P 231

EXPERIMENT D

Cycle: 10 min ON and 10 Samples taken min OFF at 5 min Inlet 15 psiFlow: 0.3 GPM (1.13 L/min) Sampling Effluent: every cycle Points: atmiddle Results First Run: 16 gallons of DI water E coli concentration100% reduction approx. 10,000 15,000 cfu/mL (2 samples) counts/mL Second10 gallons of DI water E coli concentration Run: dust 30 NTU no none E.coli Third 4 gallons of DI water E coli concentration 100% reductionRun: approx. 100,000 170,000 cfu/mL (2 samples) counts/mL Fourth 16gallons of DI water E coli concentration 100% reduction Run: approx.10,000 5050 (2 samples) counts/mL

With respect to evaluating scale control, water having 25 grainshardness was passed through the heating coil rig shown in FIG. 9. Thetesting was conducted according to test protocol DVGW 512, and theresults are shown in FIG. 10. The unfiltered water showed significantscale build up, as is visible on the right side of the test rig and asindicated below. The filtered water showed almost no scale build up, asindicated on the left side of the test rig and indicated below:

Test Results at 100° C. 25 grains hardness Untreated Filtered WaterHeating Coil 1.221 0.01 Glass Wall 0.936 0.06 Floor Base 0.198 0.03Total 2.355 0.10

Additional testing in 30 grain hardness water over 1200 liters gave thefollowing results

Test Results at 100° C. 25 grains hardness Untreated Filtered WaterHeating Coil 3.316 0.04 Glass Wall 2.171 0.03 Floor Base 0.867 0.004Total 6.354 0.074

The scale control provided by the filtration system and apparatusdisclosed herein, combined with the efficiency of removingmicroorganisms from water, makes the fluid purification system suitablefor incorporation into a wide variety of appliances that benefit fromscale control (e.g., automatic dishwashers, laundry washing machines) orfrom such microbial control (e.g., refrigerators, ice makers). The fluidpurification system described herein can be incorporated into a suitablehousing, which is plumbed into the water supply line of the appliance.

The invention having been thus described by reference to certainspecific embodiments and examples, it will be understood that thesespecific embodiments and examples are illustrative, and not intended tolimit the scope of the appended claims.

What is claimed is:
 1. A fluid purification system, comprising: a firstfluid purification media comprising a rigid porous purification block,comprising: a longitudinal first surface; a longitudinal second surfacedisposed inside the longitudinal first surface; and a porous highdensity polymer disposed between the longitudinal first surface and thelongitudinal second surface; a second fluid purification media,comprising a fibrous, nonwoven fabric that is folded to form a pluralityof pleats, and that is disposed adjacent to the first surface of thefirst purification media, adjacent to the second surface of the firstpurification media, or both.
 2. The fluid purification system of claim1, wherein said first fluid purification media further comprises a fluidpurification material comprises which carbon particles having a porosityof 50% to 90%.
 3. The fluid purification system of claim 1, wherein therigid porous purification block has an average pore diameter that rangesbetween 2,000 and 60,000 Å.
 4. The fluid purification system of claim 1,wherein: the longitudinal first surface is an outer surface having afirst transverse dimension; the longitudinal second surface is an innersurface having a second transverse dimension; and the ratio of the firsttransverse dimension to the second transverse dimension is in the rangeof 1.2 to 1.9, and the difference between the first transverse dimensionand the second transverse dimension is twice the thickness of the rigidporous purification block.
 5. The fluid purification system of claim 2wherein: the ratio of the first transverse dimension to the secondtransverse dimension is in the range of 13 to 1.5.
 6. The fluidpurification system of claim 5, wherein: the ratio of the firsttransverse dimension to the second transverse dimension is in the rangeof 1.36 to 1.5.
 7. The fluid purification system of claim 2, wherein therigid porous purification block is in the form of an cylindricalannulus, and wherein the first transverse dimension is an outer diameterand the second transverse dimension is an inner diameter of the annulus.8. The fluid purification system of claim 1, wherein the porous highdensity polymer comprises a high density polyethylene (HDPE).
 9. Thefluid purification system of claim 1, wherein the porous high densitypolymer comprises polyethylene.
 10. The fluid purification system ofclaim 9, wherein the porous high density polymer is blow molded.
 11. Thefluid purification system of claim 9, wherein the porous high densitypolymer has a void volume of 40%.
 12. The fluid purification system ofclaim 1, wherein the porous high density polymer comprises ultra highmolecular weight polyethylene.
 13. The fluid purification system ofclaim 1 wherein the rigid porous purification block comprises polymericmaterials having a micron rating of 10-150.
 14. The fluid purificationsystem of claim 1, wherein the porous high density polymer is formedfrom particles of high density polymer having an average particle sizeranging between 10 and 50 μm.
 15. The fluid purification system of claim2, wherein the carbon particles are present in an amount ranging between10 and 30% by weight, based on the total weight of the rigid porouspurification block.
 16. The fluid purification system of claim 2,wherein the fluid purification material is present in an amount rangingbetween 15 and 30% by weight, based on the total weight of the rigidporous purification block.
 17. The fluid purification system of claim 1,wherein the porous high density polymer is present in an amount rangingbetween 65 and 90% by weight, based on the total weight of the rigidporous purification block.
 18. The fluid purification system of claim 1,wherein the porous high density polymer is present in an amount rangingbetween 70 and 90% by weight, based on the total weight of the rigidporous purification block.
 19. The fluid purification system of claim 1,wherein the rigid porous purification block comprises nanoparticulatezinc oxide.
 20. The fluid purification system of claim 1, wherein theporous high density polymer comprises a void volume of 30-70 volume %.21. The fluid purification system of claim 19, wherein thenanoparticulate zinc oxide is present in an amount ranging between 0.01and 0.1% by weight, based upon the total weight of the rigid porouspurification block.
 22. The fluid purification system of claim 1,wherein the rigid porous purification block comprises 100% porouspolymer material.
 23. The fluid purification system of claim 21, whereinthe nanoparticulate zinc oxide is present in an amount of about 0.06% byweight, based upon the total weight of the rigid porous purificationblock.
 24. The fluid purification system of claim 1, wherein the rigidporous purification block further comprises alumina nanofibers.
 25. Thefluid purification system of claim 24, wherein said alumina nanofibersare present in amounts ranging between 2 and 3% by weight, based uponthe total weight of the rigid porous purification block.
 26. The fluidpurification system of claim 1, further comprising: a coating on thelongitudinal first surface of the rigid porous purification block,comprising a high density polymer.
 27. The fluid purification system ofclaim 26, wherein said coating has a thickness that is 1/40 to 1/30 ofthe thickness of the rigid porous purification block.
 28. The fluidpurification system of claim 26, wherein the coating comprises highdensity polyethylene.
 29. The fluid purification system of claim 2,wherein: the carbon particles have an average particle size in the rangeof 10-200 μm.
 30. The fluid purification system of claim 2, wherein; thecarbon particles have a size distribution such that 5-25% by weight ofthe particles are smaller than 325 mesh and 7% by weight of theparticles are larger than 80 mesh.
 31. The fluid purification system ofclaim 2, wherein; the carbon particles are obtained by reactingwood-based carbon with strong acid under pressure, to obtainacid-reacted carbon, and heating the acid-reacted carbon in a gasatmosphere.
 32. The fluid purification system of claim 2, wherein: thecarbon particles have an average particle size in the range of 10-200μm; the carbon particles have a size distribution such that 5-25% byweight of the particles are smaller than 325 mesh and 7% by weight ofthe particles are larger than 80 mesh; and the carbon particles areobtained by reacting wood-based carbon with strong acid under pressure,to obtain acid-reacted carbon, and heating the acid-reacted carbon in agas atmosphere.
 33. The fluid purification system according to claim 1,wherein the second fluid purification media is disposed adjacent to thelongitudinal second surface of the first fluid purification media. 34.The fluid purification system according to claim 1, wherein the secondfluid purification media comprises microglass structural fibers.
 35. Thefluid purification system according to claim 34, wherein the secondfluid purification media further comprises aluminum fibers or particlesor aluminosilicate fibers or particles disposed on, among, or in themicroglass structural fibers.
 36. The fluid purification systemaccording to claim 1, wherein one or more of said pleats comprise a leghaving a length ranging from 6-18 mm.
 37. The fluid purification systemaccording to claim 36, wherein said length of said pleats ranges from 7to 10 mm.
 38. The fluid purification system according to claim 34,wherein the second fluid purification media further comprises particlesof porous carbon having a porosity of 50-90%.
 39. The fluid purificationsystem of claim 1, wherein the rigid porous purification block has athickness that is at least 4.5 times a thickness of the fibrous,nonwoven fabric
 40. The fluid purification system of claim 39, whereinthe rigid porous purification block has a thickness that is at least 7times the thickness of the fibrous, nonwoven fabric.
 41. The fluidpurification system of claim 40, wherein the rigid porous purificationblock has a thickness that is at least 8.75 times the thickness of thefibrous, nonwoven fabric.
 42. A fluid purification apparatus comprisingthe fluid purification system of claim
 1. 43. A method of removingcontaminants from water, comprising contacting the water with the fluidpurification system of claim 1 at a pressure of 7-10 psi.
 44. The methodof claim 43, further comprising contacting the water with a fibrousnonwoven fabric.
 45. The method of claim 43, which comprises reducingthe bacteria content of the water by 99.99% using a flow rate of atleast 1000 cm3 per minute with an inlet pressure of 10 psi.
 46. A methodof reducing scale in water processing equipment, comprising contactingwater with the fluid purification system of claim 1 prior to or duringcontact of the water with said water processing equipment.
 47. Themethod of claim 46, wherein said water processing equipment comprises aheat exchanger.
 48. An appliance comprising: an input water line; and afluid purification system according to claim 1 disposed in said inputwaterline.
 49. The appliance of claim 48, wherein the appliance is arefrigerator, an ice maker, an automatic dishwasher, or a laundrywasher.